Originally, this was not a problem, but by the late 1950s, the turnpike was so heavily used that traffic congestion demanded expansion. The Pennsylvania Turnpike Commission (PTC) conducted studies on either expanding or bypassing the tunnels. The result was the "twinning" of four tunnels (by constructing a second, parallel, two-lane tunnel), and outright bypass and closure of the other three. The tunnels through the Blue, Kittatinny, Tuscarora, and Allegheny mountains were expanded through the "twinning" process, while the other three were bypassed. The Laurel Hill Tunnel, located on the border of Westmoreland and Somerset counties, was one of these tunnels, though the bypass was only around two miles (3.2 km) long.

The Sideling Hill and Rays Hill tunnels, on the other hand, were near each other, and a 13-mile (21 km) bypass was required. As a result, the Cove Valley Travel Plaza, which was located between the eastern portal of the Sideling Hill Tunnel and the present-day turnpike, was bypassed. It was replaced with a new Sideling Hill Travel Plaza, which, unlike the plaza it replaced, was a single building serving travelers from both directions of the highway.

Today, the Abandoned Turnpike, as it is commonly known, is a popular tourist attraction. The PTC sold most of the property to the Southern Alleghenies Conservancy (SAC) for $1 in 2001.[1] The property is managed by Friends of the Pike 2 Bike, a coalition of non-profit groups (including the SAC) to eventually convert the stretch into a bike trail. The property is officially closed to the public,[2] and no motor vehicles are allowed on the property, but bicycle riders are free to use it at their own risk. The trail requires helmets and lights. Because this stretch sits on parts of the former right-of-way of the South Pennsylvania Railroad that was never completed but later formed the basis of the mainline turnpike, this makes the Pike2Bike unofficially a rail trail. The PTC still owns a stretch of about 0.25 miles (0.40 km) on the west and 3.5 miles (5.6 km) on the east for maintenance purposes.

The entrance ways to the tunnels were in respectable shape through the early 1980s, when vandalism and time began to take their toll; thieves stole the lettering of the signs of the tunnels sometime between 1981 and 1999. The tunnels themselves are still standing and, despite not having been maintained for decades, are still structurally sound.[citation needed]

A business plan and feasibility study was completed by Gannett Fleming in 2005.[3] It proposed various ideas to make the trail as accessible as possible for cyclists, hikers, inline skaters, and equestrians.

There have also been numerous military uses for the highway; the tunnels were considered as a storage area for weapons, as was the open highway for aircraft. The military also used the highway for training soldiers for Iraq in the early 2000s, even after the highway was sold to the SAC.[5]

The site of the former Cove Valley Travel Plaza was used as a shooting range for the Pennsylvania State Police. Since the SAC bought the property, the site has not been used as a shooting range, although warning signs are still posted in the area.

In 2008 the highway was used for the filming of the Dimension Films movie The Road[6] starring Viggo Mortensen. The studios mildly restored the exterior of the eastern portal of the Sideling Hill Tunnel when it was used for filming.

End of the remaining PTC-owned stub of the Abandoned Pennsylvania Turnpike following the demolition of a bridge over US 30

In 2005, the PTC restricted access to the abandoned turnpike by demolishing an overpass over U.S. Route 30 (US 30) in Breezewood and an overpass on Pump Station Road near the site of the old Cove Valley Travel Plaza. The demolition of the overpasses removed the liability and expense of repairing the aging bridges, marked the property lines between the public and the PTC-owned sections of the property, and prevented motorized vehicles from easily entering the abandoned turnpike.

The original plans for the removal included an access road, but somewhere along the way, it was removed and not known to Pike 2 Bike officials until it was too late. As of 2012[update], the Friends of the Pike 2 Bike are seeking to obtain grants that will allow the building of an access road and to rebuild on it the last remaining original toll booth, which was obtained in 2006. The toll booth will be used to collect a parking donation that will be used to pay for maintenance. An access road was built in the late 2000s on the PTC-owned side of the former Pump Station Road overpass, making the 3.5-mile (5.6 km) section still owned by the PTC a de facto access road to the active turnpike in itself; however, like other access roads along the turnpike, it is off-limits to the public and is only used by the PTC or Pennsylvania State Police.

Access point at US 30 and Tannery Road

There are three access points to the public section of the abandoned highway:

The intersection of Tannery Road and US 30 in Breezewood sits near the western end of the turnpike, which can be reached by climbing a small hill. Parking is available in front of the orange snow fence at the bottom of the hill. Rays Hill Tunnel lies about two miles east of this point.

A parking lot exists on the trail at the eastern end of the turnpike off Pump Station Road north of US 30; the entrance is a service road just south of where a turnpike overpass was removed in 2005. This access point lies near the site of the former Cove Valley Travel Plaza and about one mile east of the Sideling Hill Tunnel.

A forest service path called Oregon Road leaves US Route 30 at that highway's intersection with Pennsylvania Route 915 in the village of Crystal Spring and runs north for several miles before reconnecting with PA 915 near Valley-Hi. Oregon Road runs parallel and adjacent to the abandoned highway for much of its length, and several clearings in the forest allow for parking and access to the road. These access points lie between the two tunnels: Rays Hill is about three miles west and Sideling Hill is about two miles east.

The PTC considered bypassing the Lehigh Tunnel on the Northeast Extension before ultimately deciding on twinning the tunnel. Cost for the bypass and unnecessary added mileage to the highway were deciding factors.[7]

The PTC has been considering bypassing the deteriorating Allegheny Mountain Tunnel to alleviate traffic congestion.[8] Boring a third tunnel is also being considered.